1. Field of the Invention
This invention relates generally to the charging of refrigeration systems, and particularly to a refrigerant charging cylinder for use with conventional refrigeration systems.
2. Description of the Prior Art
The recharging of refrigeration systems in the conventional manner employed today is very time consuming and difficult, and can be extremely dangerous. The cylinders used today will emit either refrigerant gas or refrigerant liquid, but will not emit anything in-between these two states. To carry out the conventional recharging procedure, the refrigerant cylinder is inserted into the high side of the refrigeration system with the compressor stopped. See U.S. Pat. No. 3,118,288, issued Jan. 21, 1964 to P. J. Small. Further, the refrigerant cylinder must be inverted so that the liquid refrigerant will be next to the outlet valve conventionally provided on such cylinders. When the pressure in the refrigeration system is equal to the pressure in the cylinder, the cylinder is turned right side up, connected to the suction side of the compressor of the refrigeration system, and a charge of gas drawn into the system while the compressor is running. Soon, however, the refrigerant cylinder becomes very cold as the liquid in the cylinder boils to give up gas to the top of the cylinder. Thus, the cylinder becomes very cold, and it may become necessary to pour hot water, and the like, on the cylinder in order to continue working with same. Some technicians even become so desperate as to light a torch and heat the tank portion of the cylinder in order to keep the outer surface of the tank at tolerable levels, which heating is, of course, against pertinent safety laws.
U.S. Pat. No. 3,785,163, issued Jan. 15, 1974 to W. Wagner, discloses a refrigerant charging tool and method of using same which is intended to simplify the charging of refrigeration systems. This tool, however, requires the use of an expensive and heavy charging manifold which converts liquid refrigerant into a saturated vapor which may be fed to the low, or suction, side of the refrigeration system while the compressor of the system is running. Thus, while the charging manifold of Patent No. 3,785,163 eliminates the need for carrying out a two-stage charging process by converting liquid refrigerant into a saturated vapor which is injectable into the suction side of a compressor, the refrigerant cylinder must still be inverted in order to provide liquid refrigerant to the expensive and complicated charging manifold.
It is very dangerous to invert refrigerant cylinders of the, for example, 25 pound size and up, since the relief valve on the conventional cylinders of, for example, 25 pounds, 30 pounds, and 50 pounds is built into the outlet valve arranged at the top of the tank. If a service technician should shut off the valve on a conventional refrigerant cylinder while the cylinder is in an inverted position so as to temporarily leave the charging equipment, and the charging cylinder, which may be a 30 pound tank of Refrigerant 12, and the like, is exposed to the sun, a radiator, or other source of heat, the cylinder may overheat with resulting heating of the refrigerant and possible rupture of the relief valve. With the cylinder in an inverted position, the thrust will be upward through the ruptured relief valve and the cylinder would become airborne.
Another disadvantage of the charging tool set forth in U.S. Pat. No. 3,785,163 is that a single device will not cover an entire range of standardsize refrigerant cylinders. Thus, the investment in these devices becomes greater since a set of, for example, three such charging tools must be available in order to permit one to charge a refrigeration system from any of the standard size refrigerant cylinders.
Further, the conventional refrigerant cylinders are inherently unstable and difficult to work with when they are in an inverted position. If, for example, the hose connecting the outlet valve of the cylinder to the refrigeration system comes loose from the outlet valve of the cylinder, or perhaps is knocked loose by a workman bending over trying to manipulate the outlet valve, a costly delay and possible injury to personnel may result.
Another problem in the conventional technique for recharging refrigeration systems is that it is economically unfeasible to refill the standard refrigerant cylinders of the 50 pound size and smaller. The result is that these smaller cylinders are presently being thrown away or sold as surplus, with the result that they are subject to misuse by irresponsible and uninformed parties.
It is known generally to provide valve systems which dispense vapor from a pressure vessel containing liquefied gas and vapor under pressure. Examples of such valves are shown in U.S. Pat. Nos. 2,991,918, issued July 11, 1961, and 3,258,168, issued June 28, 1966, both to G. R. Allen. U.S. Pat. No. 1,938,036, issued Dec. 5, 1933 to T. C. Martin et al, also discloses a dispensing valve which will vaporize a liquid drawn from an associated tank.